Circuit interrupter housing



June 6, 1939- H. A. TRIPLETT ET AL 2,160,926

CIRCUIT INTERRUPTER HOUSING Filed April 50, 1937 8 Sheets-Sheet 2 June 6, 1939.

H. A. TRIPLETT ET AL CIRCUIT INTERRUPTER HOUSING Filed April 30, 1957 8 Sheets-Sheet 3 June 6, 1939. H. A. TRIPLETT ET AL CIRCUIT INTERRUPTER HOUSING Filed April 30, 1957 8 Sheets-Sheet 4 9 a 9 \\W v\\\ h/ v i @ll' //H w i Y M 900 n A A w m June 6, 1939.

June 6, 1939. H. A. TRIPLETT Er AL CIRCUIT INTERRUPTER HOUSING Filed April 30, 1937 8 Sheets-Sheet 6 fg g, 17.

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June 6, 1939. H. A. TRIPLETT ET AL CIRCUIT INTERRUPTER HOUSING 8 Sheets-Sheet 8 Filed April 50, 1937 Ill/ll k II////// l f/z/ue/z i ons.-

Patented June 6, 1939 UNITED STATES PATENT OFFICE Evanston, 111., assignors to Schweitaer a Conrad, Inc., Chicago, 111., a corporation of Delaware Application April 30,

75 Claims.

Our invention relates, generally, to electric circuit interrupters and it has particular relation to housings for circuit interrupters oi the blast action are extinguishing type.

With the widespread development of underground cable systems for the distribution of electric power at high voltage, such as 4000 to 5000 volts, there has been a demand for circuit interrupters, such as fuse cutouts, for protecting them against short circuits and overloads. Since the cables are run underground and the cutouts must be likewise installed for operation underground, for practical reasons, certain problems have arisen, the solution of which has not been free from difficulty.

One of the problems has been the development of a circuit interrupter that will open the circuit automatically, either under various overload conditions or under short circuit conditions with a minimum of disturbance. This situation has been met through the use of cir cuit interrupters of the blast action arc extinguishing type, such as disclosed in the pending application of Conrad, Serial No. 470,416, filed July 24, 1930, now Patent No. 2,091,430, and in the application of Triplett, one of the joint inventors of the invention disclosed herein, Serial No. 85,700, filed June 1'7, 1936, bothof which applications are assigned to the assignee of this application. In these circuit interrupters the are caused by melting of the fusible means is subjected to a blast action by an arc extinguishing medium which is created by the heat of the arc. Interrupters of this type are now constructed in different forms, the particular embodiments mentioned being for illustrative purposes only.

Another problem that has been encountered has been the provision of a suitable housing for a circuit interrupter intended for operation under these circumstances. The solution of this problem has been made diflicult because of the requirement that the circuit interrupter be mounted under-ground where it may be subjected to damp conditions or, in many cases, partly or totally submerged. The matter has been-further complicated when circuit interrupters of the blast action arc extinguishing type are employed because of the rapid evolution of large quantities of gas from the arc extinguishing media that are employed in deionizing and putting out the arc. The circuit interrupter must be so housed that its operating characteristics will be unafiected by itsbeing mounted 5 in a damp location or even submerged and yet 1937, Serial No. 139,852

it must be adapted to take care in one way or another of the large quantities of gas that are evolved on operation of the device.

Another requirement is that the circuit interrupter be readily replaceable as a unit, either for testing purposes or for renewing it once it has operated. This means that special precautions must be taken, flrst to adequately insulate the parts that are employed for eii'ecting the replacement, and second to maintain the water tight integrity of the housing once the circuit interrupter has been replaced.

It is to the construction of such a housing in a manner tnat the products of the arc will be properly disposed of and its water tight integrity be maintained that our invention, as disclosed herein, is particularly directed.

The object of our invention, generally stated, is to provide a housing for a circuit interrupter of the blast action arc extinguishing type that will be simple in construction and which may be readily and economically manufactured and installed.

An important object of our invention is to provide for housing a high voltage circuit interrupter of the blast action are extinguishing type in such manner that it may be installed in damp locations or even submerged.

An object of our invention is to provide for venting a housing in which a circuit interrupter of the blast action are extinguishing type is mounted to dispose of the products .0! the are that are evolved when the interrupter operates.

Another important object of our invention is to provide for automatically venting a fluid tight housing containing a circuit interrupter of the blast action arc extinguishing type on operation thereof.

A further object of our invention is to provide for shunting a circuit interrupter mounted in a fluid tight casing.

Still another object oi our invention is to provide for removably mounting a circuit interrupter of the blast action are extinguishing type in a fluid tight metal casing or tank which is adapted to be grounded.

Another important object or our invention is to seal an expansion chamber formed of insulating material, such as glazed porcelain, to a housing supporting a circuit interrupter of the blast action are extinguishing type in such manner that ingress of moisture from outside or the housing is prevented and egress of the products of the arc is also prevented.

An ancillary obiect of our invention is to provide an improved terminal construction for a fluid tight housing to permit connection to a high voltage circuit interrupter mounted there- Still another object of our invention is to provide for removably mounting a circuit interrupter, such as a fuse of the blast action are extinguishing type, inside of an insulating sleeve with its terminals in contact engagement with terminals inside of the sleeve and to provide for external connection thereto.

Another object of our invention is to provide for automatically adjusting the connection between a replaceable circuit interrupter of the blast action are extinguishing type and a condenser adapted to receive and cool the products of the are that are formed on operation of the circuit interrupter.

Another important object of our invention is to provide a fluid tight non-ventable housing for a circuit interrupter of the blast action are extinguishing type.

Another object of our invention is to provide improved construction for venting the interior of a housing for circuit interrupters of the blast action are extinguishing type that are arranged to be mounted in locations where they may be subjected to damp conditions or may be partly or entirely submerged.

Other objects of our invention will, in part, be obvious and in part appear hereinafter.

Accordingly, our invention is disclosed in the embodiments hereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the constructions hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of our invention reference may be had to the following detailed description, taken in connection with the accompanying drawings, in which:

Figure 1 is a view, in front elevation, of a circuit interrupter housing constructed in accordance with our invention;

Figure 2 is a view, in side elevation, of the circuit interrupter housing shown in Figure 1;

Figure 3 is a view, similar to Figure 1, showing how the terminals of the circuit interrupter housing may be shunted;

Figure 4 is a view, in side elevation, of the circuit interrupter housing and shunt connection shown in Figure 3;

Figure 5 is a longitudinal sectional view, on an enlarged scale, of the circuit interrupter housing shown in Figures 1 through 4, a circuit interrupter of the blast action are extinguishing type being shown in operative position therein;

Figure 6 is a view, in side elevation, of the housing shown in Figure 5, certain parts being shown in section in order to illustrate more clearly the terminal housing construction;

Figure 7 illustrates diagrammatically the circuit connections that are employed in practicing our invention;

Figure 8 is a longitudinal sectional view, showing the preferred construction of the plug terminal for the shunt conductor;

Figure 9 is an enlarged fragmentary longitudinal sectional view of the fuse housing shown in Figure 5, the various parts being shown in the positions that they occupy when the circuit interrupter is in position, but with the circuit interrupter omitted in order to more clearly illustrate the relationship of the various parts;

Figure 10 is a detail sectional view taken along the line l0l0 of Figure 9;

Figure 11 is a view, in top plan, of one of the condenser plates;

Figure 12 is a view, in side elevation, of the condenser plate shown in Figure 11;

Figure 13 is a view, in top plan, of the condenser holder;

Figure 14 is a view, partly in side elevation and partly in section, showing a circuit interrupter of the liquid arc extinguishing type, such as disclosed in the copending application of Conrad, Serial No. 470,416; referred to hereinbefore, which may be employed in the housing shown in certain of the preceding figures;

Figure 15 is a view, partly in side elevation and partly in section showing a circuit interrupter of the solid material arc extinguishing type, such as shown in the copending application of Triplet-t, Serial No. 85,700, referred to hereinbefore, which may also be employed in the housings shown in the preceding figures;

Figure 16 is a fragmentary view, in side elevation, of a circuit interrupter housing with which a non-ventable insulated expansion chamber is employed;

Figure 17 is a fragmentary View at an enlarged scale partly in side elevation and partly in section, showing theconstruction of the expansion chamber and its associated parts that may be employed in the construction shown in Figure 16;

Figure 18 is a view, in side elevation, of a. circuit interrupter housing of the type herein described that is arranged to be vented downwardly;

Figure 19 is a sectional view, at an enlarged scale, of a portion of the expansion chamber as shown in Figure 18 and the connections thereto for venting it downwardly;

Figure 20 is a view, partly in side elevation and partly in section, showing a modified form of expansion chamber and connections thereto for venting it downwardly;

Figure 21 is a view, in side elevation, of a housing for a circuit interrupter of the type herein described that is arranged for venting upwardly;

Figure 22 is a sectional view, at an enlarged scale, of the expansion chamber and associated parts, shown in Figure 21; and

Figure 23 is a fragmentary sectional view of a modified form of mounting for the vent pipe shown in Figure 22.

Referring now particularly to Figures 1 and 2 of the drawings, it will be observed that the reference character 25 designates, generally, a housing fora circuit interrupter of the blast action are extinguishing type that is constructed in accordance with the present invention. The housing 25 includes a casing or tank 26, a dome or expansion chamber 21 and a handle assembly, shown generally at 26, for reniovably mounting the circuit interrupter therein. As will hereinafter appear, different types of circuit interrupter may be employed in the housing 25. It will also be presently apparent that this housing is particularly adapted for mounting underground where damp conditions may prevail or where the system may be partly or entirely submerged.

The tank 26 is preferably formed of cast iron and it has integrally formed therewith bosses 29 on the rear side to which apertured brackets 30 may be bolted, or otherwise secured, for mounting the housing 25 in operative position, such as on the wall of a vault or manhole. Ordinarily, the tank 26 will be grounded to reduce operating hazards but there may be some cases where grounding is not desired.

In order to provide for external connection to the circuit interrupter that is mounted inside of the housing 25, left and right hand terminal housings 3| and 32 are provided and secured to opposite sides of the metal tank 26, as illustrated. The terminal housings 3| and 32 are preferably formed of cast iron and each is provided with a conductor receiving sleeve 33 and 34, respectively, integrally formed therewith, for receiving line conductors 35 and 36. It will be understood that the line conductors 35 and 36 are provided with suitable insulating coverings and that they will ordinarily be provided with outside sheaths of metal, such as lead, and that they may be suitably connected into the housings 3| and 32 in a manner that will presently be set forth.

In certain instances it is desirable to shunt the circuit interrupter inside of the housing 25 so that it may be removed for inspection or otherwise while still maintaining power flow between the conductors 35 and 36. For this purpose the terminal housings 3| and 32 are provided with additional sleeves 31 and 36 that are cast integrally therewith and angularly spaced from the sleeves 33 and 34 as illustrated. Normally these sleeves 31 and 36 will not be in use and threaded covers 39 and 40 are provided for closing the open ends thereof.

While the expansion chamber 21 is shown and described herein as being preferably formed of glazed poreclain, it will be apparent that it could be formed partly or wholly of metal, A metal expansion chamber is shown in Patent 2,091,423 to Triplett which issued August 31, 1937, on an application filed October 28, 1932. Another type of metal expansion chamber is shown in Patent 2,091,424 to Triplett, issued August 31, 1937, on an application filed May 13, 1933. Both of these patents are assigned to the assignee of this application, were copending with the same, and are referred to in more detail hereinafter. Thus, whether the expansion chamber 21 is formed entirely of insulating material or is formed of metal and suitably insulated, an insulated expansion chamber is provided for receiving the products of the are that is formed on blowing of the fusible element of the circuit interrupter.

For the purpose of holding the expansion chamber 21, which is preferably formed of glazed porcelain, onto the upper end of the metal tank 26, the latter is provided with four pairs of ears 43 that are cast integrally therewith for receiving C-shaped clamps 44 on suitable pins 45 therebetween. Cap screws 46 are threaded in the upper ends of the C-shaped clamps 44 for holding a clamp ring 41, having an inverted L-shaped section in position. It will be understood that, when the cap screws 46 are unscrewed, the clamps 44 may be rotated about the pins 45 and out of the way of the clamp ring 41 so that it may be readily lifted off of the expansion chamber 21 to permit its removal.

In order to automatically vent the interior of the housing 25 to the atmosphere on operation of the circuit interrupter of the blast action arc extinguishing type mounted therein, a valve, shown generally at 46, is provided in the expansion chamber 21. The details of construction of the valve 46 will be set forth hereinafter. While it is desirable in many instances to employ the valve search 46 for venting the housing 25, it will be understood that the valve 46 may be omitted in certain constructions with the expansion chamber 21' either completely closed to the atmosphere and and non-ventable or with it vented to the atmosphere with a suitable vent pipe extending either above or below the housing 25 as the case may be.

The handle assembly 26 for removably mounting the circuit interrupter inside of the housing 25 comprises a handle shell 56, composed preferably of cast iron, that is adjustably held in position by a stud 5| having a left hand thread which is secured therein, as will hereinafter appear, and which cooperates with a correspondingly threaded handle 52, The handle 52 is rotatably mounted in a two part bail 53, the two parts of which are held together by bolts 54. The ends 55 of the parts of the bail 53 are provided with 0ppositely facing hook-shaped portions that interfit with pins 56 carried by and extending outwardly from bosses 51 that are integrally formed with a depending flange 58 from the metal tank 26. When the handle 52 is rotated in a counterclockwise direction, as viewed from underneath the housing 25 to release the handle shell 50 and to withdraw the circuit interrupter carried thereby from contact clips in the housing, the hookshaped ends 55 of the bail 53 are also released from the pins 58 and the ball then may be rotated in a clockwise direction, as viewed from underneath the housing 25, to permit removal of the handle assembly 26 and the circuit interrupter carried thereby. Further, description of the withdrawal of the circuit interrupter from the contact clips will be set forth hereinafter.

The conductors 35 and 36 may be directly interconnected and the circuit interrupter in the housing 25 shunted by the shunt connector, shown generally at 6| in Figures 3 and 4 of the drawings. The shunt connector 6| comprises an insulated flexible cable 62 having terminal assemblies 63 and 64 at its ends. In order to connect the shunt connector 6| the covers 39 and 40 are removed from the sleeves 31 and 38 to ex pose socket terminals, the construction of which will be described hereinafter.

In Figure 8 of the drawings the details of construction of one of the terminal assemblies G4 are shown. As there shown the strands 65 of the cable 62 are inserted in a socket 66 of a plug contact member, shown generally at*61. The strands 65 are soldered into the socket '66 and a pin 66 is then inserted, as shown, for further securing the strands 65 in position. A plurality of spring fingers 69 is integrally formed with the plug contact member 61, as by providing saw cuts at right angles to each other in the plug end to provide spring contact engagement with a suitable plug. A portion of the insulation of the flexible cable 62 is removed to permit the positioning thereon of a sleeve 10 formed of a suitable insulating material, such as Bakelite. Another sleeve 1|, formed of like material, is telescoped over the sleeve 10 and over the insulation of the flexible cable 62. The sleeve 1| is provided With a radial flange 12 for interfitting with an inwardly extending radial flange 13 of a clamp nut 14. It will be understood that the clamp nut 14 may be threaded onto the sleeve 36,. for example, on the same threads from which the cover 40 is removed.

The details of the internal construction of the housing 25 are illustrated more clearly in Figure 5 of the drawings to which reference will now be had. As shown, the tank 26 has mounted therein and coaxially therewith a sleeve or insulator 16 which is adapted to receive a circuit interrupter of the blast action are extinguishing type, shown generally at 11. The circuit interrupter 11 may be of the types shown in Figures 14 and 15 of the drawings or it may be of any other suitable type. The circuit interrupter 11 includes a housing or sleeve 18 having terminal furrules 19 and 88 at its ends. The ferrules 19 and 88 are arranged to have contact engagement with upper and lower contact clip assemblies, shown generally at 8| and 82, respectively. External connection to the contact clips 8| and 82 is provided by connector studs 83 and 84 which extend, as shown, radially outwardly through the opposite sides of the sleeve or insulator 16. Lock nuts 85 and 86 are provided on the threaded inner ends of the connector studs 83 and 84 for holding them in position. Sleeves 81 and 88, formed of suitable insulating material such as glass, porcelain, or Bakelite, surround the connector studs 83 and 84 intermediate their ends for insuring insulation thereof from the metal tank 26 and the terminal housings 3| and 32. Each of the connector studs 83 and 84 may be provided with slabbed off portions, such as shown at 89 on the stud 83, on opposite sides to permit the use of a wrench in assembling these studs.

The details of construction of the upper and lower contact clips 8| and 82 and the assembly thereof in the sleeve or insulator 16 are shown more clearly in Figure 9 of the drawings. Each of the contact clips 8| and 82 includes a contact ring 9| and 92. These rings 9| and 92 are of such external diameter that they snugly fit in the inner bore of the sleeve or insulator 16. The inner ends of the connector studs 83 and 84 are positioned in suitably threaded apertures, as shown. When the lock nuts 85 and 86 are tightened on the washers 93 and 94, the contact rings 9| and 92 are securely held in position. Secured to each of the contact rings 9| and 92 is a contact clip shell 95 and 96, respectively. Each of the contact clip shells 95 and 96 has integrally formed therewith a plurality of spring fingers 95 and 96 which are suitably curved to have contact engagement with the ferrules 19 and 88 of the circuit interrupter 11, .shown in Figure 5 of the drawings. It may not be desirable to depend solely upon the spring fingers of the contact clip shells 95 and 96 for the entire contact pressure with the ferrules 19 and 88. Accordingly, garter springs 91 and 98, in the form of coil tension springs, are provided around the outwardly curved upper ends of the contact fingers 95 and 96' to insure suitable contact pressure.

With a view to providing contact engagement between contact clip shell 95 and the contact ring 9|, to support the former securely on the latter, and to provide a maximum degree of fiexibility for the contact fingers 95' and 96', the shell 95 is provided with an outwardly radially extending flange 99 at its lower end and a depending flange I88 from the contact ring 9| is rolled over the flange 99, as shown. After the rolling operation has been completed the shell 95 is sweated to the contact ring 9|. It will be observed that the internal surface of the contact ring 9| is so formed that a space |8| is left between it and the fingers of the contact clip shell 95. This construction affords a high degree of flexibility for the contact fingers 95 so that they will be freely movable into contact engagement with the upper ferrule 19 of the circuit interrupter 11.

The contact clip shell 96 is secured to the contact ring 92 by the provision therein of a circumferential groove I82 into which a portion I83 of the skirt of the contact clip shell 96 is rolled. An aperture I84 extends through the contact ring 92 and into the groove I82. As shown a slight space is left between the portion I83 and the bottom of the groove I82 for receiving molten solder through the aperture I84 to sweat the contact clip shell 96 securely to the contact ring 92. Flexibility of the contact fingers 96 is insured by the provision of the space I85 between them and the upper portion of the contact ring 92.

Since the clip shells 95 and 96 are secured to or adjacent the lower edges of the contact rings 9| and 92 and the contact fingers 95 and 96' extend' through and slightly beyond them, a relatively long free length of contact finger is available within a relatively small overall length of contact clip. This is important when it is recalled that space is at a premium within the housing 25.

The contact rings 9| and 92 are further secured inside of the sleeve or insulator 16 by dog point set screws I81 and I88. As shown these set screws I81 and I88 are positioned in suitably threaded apertures in the wall of the sleeve or insulator 16 and the dog points thereof extend into suitable apertures in the contact rings 9| and 92. Since the contact rings 9| and 92 fit snugly inside of the sleeve or insulator 16 the two point suspension thereof is all that is required to hold them in proper relation while the circuit interrupter 11 is being inserted or removed. As shown in Figure 5 of the drawings, the terminal housings 3| and 32 are secured to opposite sides of the metal tank 26 by cap screws I89 and H8, suitable gaskets III and H2 being interposed therebetween to provide a fluid tight joint. Since the terminal construction inside of each of the housings 3| and 32 is the same, a detailed description of one of them will sufilce. For this purpose reference may be had to Figures 5 and 6 of the drawings.

As shown in these figures of the drawings, the outer end of the connector stud 83 is somewhat reduced in diameter for receiving a pair of contact clamps II3. These contact clamps 3 are provided with split apertured portions for positioning on the outer end of the connector stud where they may be secured in the desired position by screws II4, only one of which is shown in Figure 6. Each of the contact clamps II3 is provided with a threaded boss I|5 for receiving terminal sockets H6 and H1. As shown in Figure 6, the terminal socket H6 is provided with a longitudinal aperture II8 for receiving the spring contact fingers 69 of the shunt connector contact member 64, as shown in Figure 8 of the drawings. The socket member ||1, Figure 5, is provided with a plurality of spring fingers M9 for contact engagement with a terminal plug I28 that is arranged to receive the strands I2| of the line conductor 36.

It is essential that the electrical connections inside of the sleeves 34 and 38 of the terminal housing 32 be fully insulated so that there will be no liability of grounding the circuit to the housing. An insulating material, such as porcelain, is well adapted to provide the desired insulation but it has heretofore not been considered practical to use this material for insulating the electrical connections in the housing 32. The chief difliculty that has been encountered is the provision of suitable means for mounting porceof the socket member I I1, thereby opening the.

lain insulators inside of the terminal housing 32 in fluid tight relation and in such manner that they will not be cracked or broken during assembly or after the device is placed in service. These difficulties have been overcome by the provision of the porcelain bushings or insulators I22 each of which is provided with an inwardly extending flange I23 for mounting it on the respective socket members H3 and H1. It will be observed that these socket members are provided with suitable flanges for interfltting with the inwardly extending flanges I23, together with suit-. able gaskets between the flanges and the threaded bosses II into which the socket members H3 and H1 are threaded. For making the fluid tight connection with the terminal housing 32 each of the sleeves 34 and 33 is provided with an inwardly extending flange I24 that is beveled on the outer face as shown. The inner ends of the bushings I22 are slightly reduced in diameter as compared to the outer ends and are spaced slightly from the inner peripheries of the flanges I24. A rubber gasket I25 is disposed around the shoulder formed between the intermediate ends of the bushing I22 and abutting the beveled face of the flange I24. A gland I23, in the form of a metal ring having its inner facebeveled as shown, is' next disposed in engagement with the outer edge of the rubber gasket I25. The inner diameter of the gland I23 is such that it is spaced from the periphery of the bushing I22. A packing nut I21 is threaded inside of each of the sleeves 34 and 33 and, on being tightened, forces the gland I23 into engagement with the rubbergasket I25 which is deformed thereby into engagement with the bushing I22 and between the beveled faces of the flange I24 and the gland I23. The internal diameter of the packing nut I21 is such that its inner periphery is spaced slightly from the outer surface of the bushing I22. In this manner a resilient support for the bushing I22 is provided in each of the sleeves 34 and 33 and they do not come into direct engagement with any portion of the terminal housing 32. This construction provides a fluid tight mounting of the bushings I22 and at the same time cracking or breakage thereof during assembly or service is avoided.

When the shunt connector 3| is used, it will be understood that the sleeve 13 is inserted into the bushing I22 that surrounds the socket member H3 and that, when the spring contact fingers 33 are inserted in the longitudinal aperture II3, the sleeve 13 surrounds the socket member I I3.

In Figure 7 of the drawings, the circuit connections that are employed are illustrated. As there shown, the line conductors 35and 33 are interconnected by the circuit interrupter 11. This is shown in the form of a fuse wire. The line conductors 35 and 33 are also connected to the socket members H3 in the terminal housings 3| and 32 for receiving the terminals 33 and 34 of the shunt connector 3|.

As shown in Figures 5 and 6 of the drawings, the bushing I22 in the sleeve 34 is surrounded at its lower end by a terminal bell I23 which may be secured by a clamp nut I23 to the threaded lower end of' this sleeve. The lead covering of the line conductor 35 may be sealed to the lower end of the terminal bell I23 as by a wiped joint I33. It will be understood that, when the clamp nut I23 is unscrewed, the line conductor 33 may be disconnected by withdrawing it from the terminal housing 32. Since the terminal plug I23 is secured as by soldering to the strands I2I, it will be withdrawn from the contact fingers H3 circuit at this point. This plug-in type of connection is desirable for the purpose of permitting the replacement of the housing 25 without disturbing the wiped joint I33 at the lower end of the terminal bell I23.

The sleeve or insulator 13, shown in Figure 5 of the drawings, is preferably formed of asphalt impregnated flber and is of such length that it extends well beyond the ends of the circuit interrupter 11. Moreover, it is of such length that it extends beyond the upper and lower ends of the metal tank 23 in order to provide adequate insulation for the circuit interrupter 11 therefrom. It will be observed that the upper and lower ends I33 and I31 of the sleeve or insulator 13 are slightly reduced in external diameter from the intermediate portion. The lower end I31 fits snugly in an aperture at the lower end of the metal tank 23 and extends, as illustrated, into the handle shell 53.

In order to support the circuit interrupter 11 and to provide for removably mounting it within the sleeve or insulator 13, an insulating pillar I33, preferably formed of porcelain, is carried by the handle shell 53 within a suitable cup-shaped receptacle I33 to which it may be secured as by cement or otherwise. At its upper end the pillar I33 is provided with a metal boss I43, that may be cemented therein, and it is provided with a threaded aperture I, Figure 9, for receiving a threaded stud I42 that depends from the lower ferrule 33. This construction is provided so that the circuit interrupter 11 may be withdrawn from the contact clips 3I and 32 when the ball 53, Figure 6, is disconnected and the handle assembly 23 is moved downwardly relative to the housing 25. It will be noted that the threaded stud 5I, forming a part of the handle assembly 23, is further secured in the handle shell 53 by a pin I43, Figure 5, that is driven into a suitably drilled aperture.

Since the housing 25 is intended for positioning under ground where it may be subjected to damp conditions or may be partly or totally submerged, it is essential that a fluid-tight connection be provided between the handle shell 53 and the lower end of the metal tank 23. For this purpose a soft rubber gasket I44 is provided inside of the depending flange 53, around the lower end I31 of the sleeve or insulator 13 and in alinement with the outer rim of the handle shell 53. As shown in Figure 5 of the drawings, a suitable circumferential groove inside of the flange 53 is provided for receiving the soft rubber gasket I44 and confining it when the handle shell 53 is moved into fluid-tight engagement therewith by rotation of the handle 52 on the left hand threaded stud 5|. It will be noted that this construction provides a fluid-tight connection at the lower end of the tank 23 and yet readily permits the removal of the handle shell 53 when it is desired to replace or inspect the circuit interrupter 11.

In addition to compressing the gasket I44, rotation of the handle 52 on the stud 5| forces the circuit interrupter 11 into and out of engagement with the contact clips M and 32. This action is important since a relatively large force is required to insert the ferrules 13 and 33 into and remove them from contact engagement with the contact fingers 35' and 33'. This force may be more than could be directly applied by the lineman.

The reduced 'upper end portion I33 of the sleeve or insulator 16 projects through a close fitting hole in a tank seal plate I45 that is formed of a suitable insulating material, such as Bakelite. The tank seal plate I45 is secured to an integrally formed inwardly extending fiange I46 of the metal tank 26 by means of screws I41. A tank seal gasket I48 preferably in the form of a soft rubber ring, is disposed between the under side of the tank seal plate I45 and the upper surface of the flange I46.

With a view to further insulating the electrical connections inside of the housing 25 from the metal tank 26 and to securely hold the sleeve or insulator 16 in position, the tank 26 is filled with a filling of insulating compound I49. The compound I49 is sold under the name of Minerallac, its principal ingredient being refined asphalt to which h 5 been added relatively small amounts of rosin and other materials to secure the desired fusion temperature and plasticity. It will be understood that any other suitable insulating compound having the necessary insulating and plastic characteristics may be employed without departing from the scope of our invention.

The compound I49 is heated and poured into the metal tank 26 after the sleeve or insulator 16, the terminal connections thereto, and the terminal housings 3I and 32 have been assembled in the relations shown in Figure 5 of the drawings. For purposes of assembly the tank seal plate I45 is placed in position. Before the compound I49 is poured into the tank 26 the tank seal plate I45 is removed and replaced by a metal spider having a number of large holes through which the molten insulating compound I49 may be readily poured. A plug I50 in the upper portion of each of the terminal housings 3| and 32 is removed in order to permit the compound I49 to completely fill these housings. As soon as the level of the compound I 49 in the tank 26 reaches the openings from which the plugs I 50 are removed, they are replaced and the filling process is continued until the tank 26 is completely filled. The compound is then permitted to cool and, on solidification, it shrinks away from the spider that is substituted for the tank seal plate I45. This shrinkage is compensated for by adding more molten compound until it reaches a level corresponding to the top of the tank seal gasket I48. The metal spider is then removed and a small amount of molten compound is poured on top of the solidified compound. While it is still molten, the tank seal plate I45 is replaced and the screws I41 are tightened to secure it in position, a tight seal being formed at the outer and inner edges of the tank seal plate I45.

When the circuit interrupter 11 of the blast action are extinguishing type is employed, it is desirable to provide for cooling and condensing the products of the are that are formed when the device is called upon to operate. For this purpose a condenser, shown generally at I55, Figure 5, is provided. The theory of operation of the condenser I55 in connection with a circuit interrupter of the blast action are extinguishing type is fully described in the copending application of Triplett, Serial No. 639,939, filed October 28, 1932, now Patent No. 2,091,423, and the copending application of Triplett, Serial No. 670,884, filed May 13, 1933, now Patent No. 2,091,424, both of which patents are assigned to the assignee of this application. It will be sufficient for the purposes of this application to point out that the condenser I 55 is located in the upper end of the sleeve or insulator 16 in S position as to receive the products formed by the arc for extinguishing the same by the blast action of the arc extinguishing material which is created by the heat of the arc. The condenser I55 comprises a plurality of condenser plates I56, Figures '11 and 12, which may be formed of copper and which may be mounted on a condenser stem I51 and secured thereto in spaced apart relation. As shown in Figure 11, each condenser plate I56 is provided at its periphery with a plurality of radially extending fingers on which the products of the arc impinge. In assembling the condenser I55 the condenser plates I56 are mounted on the stem I51 in alinement and then successive plates are given a slight radial twist so that spiral, rather than longitudinal, grooves will be provided through which the products of the arc may flow. This spiral arrangement of the grooves between the fingers exposes a greater portion of the area of each of the fingers to the products of the arc and thereby increases the cooling and condensing action thereof.

The condenser stem I51 is threaded into a suitably tapped aperture in a spider-like condenser holder I56, Figure 13, that is provided with external threads for interfitting with corresponding internal threads in the upper end of a condenser housing I59. The condenser housing I59 is cylindrical in shape and fits closelywithin the upper end of the sleeve or insulator 16.

Since the condenser I55 will be subjected to considerable outward pressure when the circuit interrupter 11. is called upon to operate under heavy overload or short circuit conditions, it is desirable that it be securely fastened in position. For this purpose four dog point set screws I 60 are provided in suitably shaped and threaded apertures in the wall of the sleeve or insulator 16 and they extend through a split bearing ring I6I, Figures 9 and 10, into suitable drilled apertures in the lower end of the condenser housing I59. It will be observed that the bearing ring I6I is snapped into a suitably shaped groove on the inner surface of the sleeve or insulator 16 so that the upward thrust applied to the condenser I55 is substantially uniformly distributed along the wall thereof.

A comparatively tight fitting connection should be provided between the upper end of the circuit interrupter 11 and the lower end of the condenser housing I59 so that all of the products of the arc will flow into the condenser I55. Since these products of the are are of a conducting nature it is highly undesirable that they flow into the sleeve or insulator .16 where they might provide a conducting path between the terminal clips BI and 82 resulting in a fiashover therebetween. Since the condenser I55 is mounted inside of the sleeve or insulator 16 and the circuit interrupter 11 is placed in operative position from the opposite end, it is desirable that some means he provided for automatically interconnecting the upper end of the circuit interrupter 11 and the lower end of the condenser I55. Moreover, this connection should be such that slight differences in position of the circuit interrupter 11 in the sleeve or insulator I6 will not affect its proper functioning.

By means of the telescopic connection, shown generally at I62, Figure 5, these conditions are met. The details of construction of this connection are shown more clearly in Figure 9 of the drawings. As there shown this connection includes a bumper ring I63 that has integrally formed therewith an annular flange I64 that is Lil) arranged to slide over an annular flange I which depends from the lower end of the condenser housing I59. The bumper ring I88 has its inner periphery I88 curved in such manner as to receive the beveled upper end of the ferrule 19 of the circuit interrupter 11. When the circuit interrupter 11 is removed, the bumper ring I83 slides downwardly until it rests upon the upper ends of the fingers forming a part of the contact clip shell 95. Interposed between a radial flange of the bumper ring I89 and the underside of the condenser housing I59 is a resilient member I81 in the form of a. rubber ring or rubber bumper which not only is adapted to absorb the shock received by the bumper ring when the circuit interrupter 11 is inserted in position but also it serves to bias the bumper ring I63 into contact engagement with the upper end of the ferrule 19. Since the rubber bumper I61 is compressible to various degrees, the necessary tight connection with the upper end of the ferrule 19 is provided even though the circuit interrupter 11 is not always positioned in exactly the same place in the sleeve or insulator 18 or is not always provided wth the same spacing between the ferrules 19 and 80'.

.The products of the are from the condenser I are directed to the upper end of the dome or expansion chamber 21 by an exhaust tube I10, made of Bakelite" or other suitable insulating material, that may be secured as by screws I1I to the condenser holder I58, Figure 5. In the event that the pressure generated within the expansion chamber 21 on operation of the circuit interrupter 11 is sufliciently great, the valve 48 will be opened to vent it to the atmosphere. As shown, the valve 48 is positioned in a valve aperture I12 in the expansion chamber 21 that is alined with the exhaust tube I10 and the condenser I55. The upper and lower surfaces of the expansion chamber 21 adjacent the valve aperture I12 are ground in such manner that these surfaces will lie in parallel planes. These surfaces are provided for receiving a valve seat member I13, the body portion I14 of which extends downwardly through the valve aperture I12, and a gas baffle I15 that is threaded on the lower end of this body portion. A gasket I18, formed preferably of a putty-like gasket material, is spread onto the upper surface of the expansion chamber for receiving .the valve seat member I13 while a suitable gasket I11, such as a copper faced asbestos gasket, is provided between the under surface and the gas baflie I15. It will be understood that the gas baflle I15 is screwed tightly onto the body portion I14 of the valve seat member I13. It will be noted that the gas baffle I15 extends to a position slightly outside of the exhaust tube I10 so that all of the products of the arc impinge directly thereon or flow directly through the body portion I14 of the valve 48. The valve seat member I13 is provided with an integrally formed valve guide I18 within which a valve stem I19 is slidably mounted. At its upper end the valve stem. I19 has threaded thereon a valve member I80, the outer periphery of which is provided with a groove opening downwardly for interfitting with a. rim I8I formed integrally with and extending upwardly from the valve seat member I13. A rubber gasket I82 is positioned, as illustrated, in this groove and it engages the upper surface of the rim I8I in fluid-tight relation when the valve 48 is closed. A coil compression spring I83, surrounding the valve stem I19 and reacting between the IIVUI valve guide I18 and a gas banle I84, threaded on the lower end of the valve stem I19, serves to bias the valve 48 to the closed position. A nut I85 is provided for locking the gas baflie I84 in position. The gas baflle I84 is provided for initiating the opening of the valve 48 by the blast resulting from the flow of the products of the are before sufficient pressure is generated within the expansion chamber 21 to compress the spring I83 and lift the valve member I80 off of the valve seat member I18. This initiation of the opening movement of the valve 48 is desirable in order to quickly vent the expansion chamber 21. The gas pressure within the expansion chamber 21 may, under certain interrupting conditions, such as heavy overloads or short circuits, increase with extreme rapidity with the result that the expansion chamber 21 may be subjected to excessive stresses before the valve 48 has had an opportunity to open.

As set forth hereinbefore it is highly desirable that the expansion chamber 21 be sealed to the metal tank 28 in such manner that the ingress of moisture from the outside is prevented as well as the egress of the products of the arc from the interior of the expansion chamber. Special precautions are taken in forming these seals so that these conditions will be met.

It will be observed that the porcelain expans on chamber 21 is provided on its under surface with inner and outer depending lips I88 and I81 thereby forming a downwardly opening annular groove I88 therebetween. These lips are formed when the expansion chamber 21 is cast and the glazed surface covers them. With a view to providing for hermetically sealing these lips I86 and I81 and, since the glazed surface on these lips is usually somewhat irregular, a sufiicient portion is removed therefrom by suitable grinding operation so that the desired plane surfaces will be had. The grinding operation is carried out in such manner that the lower surface of each of the lips I86 and I81 is in a plane and these planes are preferably coplanar. A rim I89 formed integrally with the metal tank 26 at its upper end has its upper surface machined in a plane that is parallel to the plane of the lower surface of the lip I81. A gasket I90, preferably formed of relatively hard rubber gasket material, is interposed between the lip I81 and the This material is used with two purrim I89. poses in mind, first to provide a gasket of suffic ent strength to resist the stress applied by the C-shaped clamps 44 and second to prevent the ingress of moisture from outside of the housing 25. Any other suitable material may be emnloyed but we have found that rubber is particularly well suited for this application. Between the clamp ring 41 and the upper surface of the integrally formed radially extending flan e I9I of the porcelain expansion chamber 21 is a gasket I92. preferably formed of cork, for the purpose of preventing the clamp ring -11 from co ning into direct contact with the porcelain. The skrt I93, forming a part of the clamp ring 41, extends downwardly a sufficient distance to surround the joint between the lip I81 and the rim I89.

Egress of the products of the are inside of the expansion chamber 21 is prevented by a ga I94. preferably formed of soft rubber, and int. posed between the undersurface of the inner lip I86 and the upper surface of the tank seal plate I45. A material such as soft rubber is employed in order to provide for intimate engagement with the ground undersurface of the lip. A packing retainer I95, preferably in the form of a ring of s cork, is provided around the upper end I36 of the sleeve or insulator 18 and between it and the inner surface of the gasket I94 to insure that it will be held in position. If the soft rubber gasket 894 were not provided, it is possible that an arc might be formed to the screws I41 by the products of the are, which are conducting, coming into contact with them. Since these screws are threaded into the metal tank 26, which is grounded, a fiashover to ground might take place. This is prevented by the provision of the gasket 94. The gasket I94 is made of relatively soft rubber in order to insure that, in addition to making a fluid-tight joint between the expansion chamber 21 and the tank seal plate, it will yield enough to allow a tight joint to be made with the relatively hard rubber gasket I90 between the outer lip I81 of the dome 21 and the rim I89 of the tank 28. If both gaskets I90 and I94 were composed of material having the same mechanical characteristics, it would be diflicult, if not impossible, to keep both joints fluid-tight.

In Figure 14 of the drawings the construction of the circuit interrupter 11 is shown in greater detail. Since the construction and operation of he circuit interrupter 11 are fully described in the copending application of Conrad, Serial No. 470,416, a detailed description thereof will not be set forth herein except as is necessary to describe the present invention and the particular adaptations of the circuit interrupter 11 for use in the housing 25 described hereinbefore.

As set forth, the circuit interrupter 11 includes a sleeve or housing 18 and this is preferably formed of glass. Ferrules 19 and 80 are secured to the ends of the glass sleeve 18 by any suitable means such as by cementing them in position. The lower ferrule 80 is provided with a threaded stud I42 and it may be screwed into the tapped hole MI in the boss I40, Figures 5 and 9, that is arried by the pillar I38. This threaded connection permits the withdrawal of the circuit interrupter 11 by grasping the handle 52 and, since he pillar I38 is composed of porcelain, there is little chance of accidental contact with a live part of the circuit.

The circuit interrupter 11 is of the liquid arc extinguishing type and it is provided with a normally stationary terminal 200, carriedby a terminal support spider MI, and a relatively movable terminal 202 that is arranged to be retracted by a tension coil spring 203. One end of the. spring 203 is connected to the terminal 202 wh le the other end is suitably connected to the lower ferrule 80, as illustrated. A flexible shunt conductor 204 interconnects the terminal 202 and the ferrule 80 to provide a low resistance current path therebetween. The terminals 200 and 202 are interconnected by a fusible element 205, preferably composed of silver, and a strain element 208, preferably composed of a nickel-chromium alloy, which relieves the fusible element 205 of any tension stress that might be otherwise applied by the spring 203. The elements 205 and 296 are positioned inside of an arcing tube 201, preferably composed of insulating material such as Bakelite, that is supported by a mounting washer, also preferably formed of insulating material such as Bakelite, that is threaded, as illustrated, into the upper ferrule 19. The sleeve 18 isfilled with liquid arc extinguishing material to the level indicated by the broken line and it is forced to flow into the arcing tube 201 on melting .lite.

tu rba-nce.

of the fusible and strain elements 205 and 208 by a liquid director 209 that is carried by the movable terminal 202. A releasable vent cap H0" is sealed into the upper end of the ferrule 19 to hermetically seal the device.

On operation of the circuit interrupter 11 under heavy overload or short circuit conditions, the vent cap 2I0 will be blown out of the upper end of the ferrule 19 and it will strike the conical point 2II, Figure 5, of the condenser stem I51 10 where it is deformed and thus falls back into the upper ferrule 19. In this position the vent cap 2I0 does not interfere, as a practical matter, with the flow of the products of the are into the condenser I55 and removal thereof is insured when 15 the circuit interrupter 11 is removed.

In Figure 15 of the drawings a circuit interrupter 11 of the solid arc extinguishing material type is illustrated. This circuit interrupter 11' may be employed in the housing 25 in place of m the circuit interrupter 11 of the liquid are extinguishing type. The details of construction and operation of the circuit interrupter 11' are fully set forth in the copending application of Triplett, Serial No. 85,700, and, therefore, no further de- 25 scription will be set forth herein other than appears to be necessary to disclose the present invention.

The circuit interrupter 11 includes a tubular sleeve 18' which may be formed of glass or, as 30 shown, of an insulating material such as Bake- When such material is employed snap rings 2|3 are provided in suitable grooves adjacent the ends. These rings are externally threaded for receiving internal threads of the fer- 3 rules 19' and as illustrated. If the sleeve 18' were formed of glass, the ferrules 19 and 80 would be suitably constructed to permit their being secured in position by cement.

The circuit interrupter 11 is provided with a g renewable cartridge 2 that may be secured in position by a clamp nut 2I5 to the upper end of the ferrule 19'. The cartridge 2|4 includes a movable rod-like terminal 2I6 that is positioned in a main bore 2I1 of a body of are extinguishing material 2! which may comprise magnesium hydroxide or boric acid or any other like material which will evolve in a vapor in the presence of an are that will assist in extinguishing the arc with a. minimum of dis- M The body of arc extinguishing material 2I8 may either be a single solid body or it may be made up of several sections, as illustrated. A cartridge tube 2I9, formed of a suitable insulating material, such as Bakelite, 5 surrounds the body of arc extinguishing material 2I9. A fusible element 220, preferably in the form of a silver wire is provided for interconnecting the rod-like terminal 2I6 with the ferrule 19'. The fusible element 220 is positioned in an arcing chamber that is formed, in part, by a ring 22I of insulating material that is flared outwardly as shown.

The rod-like terminal 2I8 is arranged to be retracted by a coil tension spring 222 that is 64 interconnected between it and the lower ferrule 80. Flexible conductors 223 serve to form a low resistance current path between the terminal H6 and the lower ferrule 80'.

With a view to preventing the application of TI any tension stress to the silver fusible element 220, a strain element 224 is provided and is positioned in an auxiliary bore 225 of small diameter in the body of arc extinguishing material 2I8. As illustrated, the strain element 224 is 1 interconnected between a pin 226 extending through the lower end of the rod-like terminal 2I6 and a strain wire pin 221 that is carried by and extends inwardly from a cartridge ferrule 228. When the fusible element 228 and the strain element 24 blow, portions thereof are ex-, pelled'through the central opening in the cartridge ferrule 228. This opening is normally closed by a readily expellable disc or plate 29 of suitable insulating material, such as mica, and it is held in position by a retaining ring 238.

When the current flows through the circuit interrupter 11' it is suflicient to melt the fusible element 228, the current flow is then transferred to the strain element 224 and it melts. The strain element is constructed, as described in the copending application of Triplett, Serial No. 85,700, in such manner that it will melt at its upper end, thereby releasing the tension spring 222 for retracting the rod-like terminal 2I5 in the main bore 2I1. For low current interruption the arc is drawn and extinguished in the auxiliary bore 225 by the evolution of vapor from the inner wall thereof. The continued movement of the rod-like terminal 2I6 prevents the are from restriking.

During short circuit interrupting conditions the current transfers from the fusible element 228 to the strain element 224 in this same manner. However, under this operating condition, the entire section of the strain element 224 may fuse and the arc may be reestablished in the main bore 2I1 before any appreciable movement oi the rod-like terminal 2I5 takes place. But in this case the larger bore is adapted to extinguish the arc.

The vapor that is evolved from either of the bores 2I1 or 225 by the heat of the arcs drawn therein will flow upwardly through the central opening in the cartridge ferrule 28, carrying with it the thin disc 229. These products of the are are, in the case that a material such as boric acid is employed for the arc extinguishing material 2I8, composed principally of water vapor which may be readily condensed. Advantage is taken of this characteristic in the construction of a circuit interrupter housing to be presently described.

In Figures 16 and 17 of the drawings a circuit interrupter housing construction is disclosed in which advantage is taken of the fact that the products of the arc from a circuit interrupter of the solid arc extinguishing material type may be readily condensed,'thereby not requiring that they be vented to the atmosphere, as is generally the case when a circuit interrupter of the liquid arc extinguishing type is employed. As shown, the metal tank 26 is employed and its interior construction is as shown in Fig. of the drawings and described hereinbefore. However, an expansion chamber 235 is provided which is somewhat larger than the expansion chamber 21. The expansion chamber 235 is preferably formed of porcelain and it is nonventable. It may be secured to the tank 25 in fluid-tight relation by the clamps 44 in the manner described hereinbefore.

As shown more clearly in Figure 17 the condenser support I58, that is threaded into the upper end of the condenser housing I59 in the upper end I35 of the sleeve that houses the cir cuit interrupter, is provided with an exhaust tube 236 that is somewhat longer than the exhaust tube I18, of Figure 5. The products of the arc, after they have passed through the condenser, are directed by the exhaust tube 236 against a gas bame 231 which may be cemented to the upper end of the expansion chamber 235 as shown.

In some cases it may be desirable to provide for directly venting the expansion chamber 21 rather than to provide the valve 48 for automatically venting it or for constructing it so that it will be non-ventable as is the case with the expansion chamber 235. For this construction it is desirable that the venting arrangement be such that the interior of the housing will not be filled with water in the event that the housing is submerged.

A construction satisfying these requirements is shown in Figures 18 and 19 of the drawings. As

there shown the valve 48 has been omitted from the porcelain expansion chamber 21 and in its stead an inverted U-shaped metal tube 248 has been substituted. The tube 248 is connected to a pipe 2 that is formed of suitable insulating material, such as asphalt impregnated fiber, and it extends downwardly through brackets 242, as illustrated, which may also be employed to support the tank 26. The insulated pipe 242 extends below the tank 226 to such a distance that a water seal will be formed therein when the tank 26 is partly or wholly submerged.

The details of construction are shown more clearly in Figure 19 A sleeve 248 extends through the aperture I 12 in the expansion chamber 21 and the gas bame I15 is threaded onto its lower end. Suitable gaskets are provided, as shown, to make the connection Jfluid-tight. A bolt 244 extends through the pipe 248 and is threaded at its lower end into a spider 245 extending from the sleeve 248. At its other end the pipe 248 is provided with a bolt 245 that is threaded into a spider 241 of a connecting member 248. The upper end of the insulated pipe 24! may be threaded into the connecting member 248.

While the insulated pipe 2 has been shown as being mounted in the brackets 242 that support the tank 25, it will be understood that it may be mounted independent of these brackets. It should be borne in mind, however, that the pipe 2 ,should be so located that water will not get into the expansion chamber 21 when the housing is partly or wholly submerged.

Instead of employing the construction shown in Figures 18 and 19 of the drawings for venting the expansion chamber, the construction shown in Figure 20 may be employed. As there shown, a porcelain expansion chamber 258 is provided having an offset portion I for registering with a corresponding offset portion 252 of a metal tank 25. Except for the offset portion 252, the metal tank 26' and the interior construction thereof are as shown in Figure 5 of the drawings. The tank 28' is filled with a suitable insulating compound I48, as previously described, and a tank seal plate 253, of appropriate shape, is provided over it. A retaining plate 254 is provided above the tank seal plate 253 for holding the soft rubber gasket 255 in position. The details for sealing the expansion chamber 258 are essentially as described hereinbei'ore in connection with the description of the manner in which the expansion chamber 21 is sealed to the tank 26 and will not be repeated.

The expansion chamber 258 may be vented by a vent pipe 256 that extends through an internally threaded flange 251 in the oflset portion 252 of the tank 25' and up into the expansion chamher 258 through the plates 253 and 254. The vent pipe 256 is preferably formed or insulating materlal such as asphalt impregnated fiber. At least its upper end should be formed or" such material until a point well below the offset portion 252 is reached in order to prevent arcing over to ground.

Instead of venting the expansion chamber 2'l downwardly, as shown in Figure 18 of the drawings, it may be vented upwardly as shown in Fig ures 21 and 22 of the drawings. For this purpose a vent pipe 266 is threaded into a suitable sleeve fitting 2! in the aperture I12 of the expansion chamber 27 and it extends upwardly for a distance that will be well above the level of any water in which the housing may be submerged. For this construction a somewhat larger condenser 262 may be employed for cooling and condensing the products of the arc. The condenser 262 will be-mounted in the upper end 263 of the sleeve or insulator 16' in the manner described hereinbefore for the condenser [55, shown in Figure 'of the drawings. The condenser-262 is provided with a somewhat longer condenser housing 264 for mounting therein the condenser plates 265 on the condenser stem 266. As shown the condenser stem 266 is carried by a condenser support member 261 that may be similar in construction to that of the condenser holder I56, Figure 13.

In the event that the circuit interrupter mounted in the housings, constructed as shown in Figures 18 and 21, should be called upon to operate when submerged, it is possible that a flashover to ground might occur since the U-shaped tube 240 and the sleeve fitting 26l are formed of metal. This action might occur since these members would thus be in contact with the water outside and with the conducting products of the are on the inside. Possibility of such a condition arising may be obviated in the use of the construction shown in Figure 23 of the drawings.

As there illustrated, the vent pipe 266 is threaded into the upper end of a sleeve 210 onto the lower end of which the gas baflle H5 is threaded. The sleeve 210 is formed of a suitable insulating material, such as a molded insulating material. In this manner the conducting products of the are do not come into contact with any metal parts that may be submerged when the interrupter opens the circuit under such a condition.

Since certain further changes may be made in the foregoing constructions and diflerent embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter set forth in the foregoing dcscription or shown in the accompanying drawings shall be interpreted as, illustrative and not in a limiting sense.

We claim as our invention:

1. A fluid-tight housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a metal tank, means removably mounting the circuit interrupter therein in insulated spaced relation, an insulated expanson chamber for receiving the products of the arc resulting from the blast action, and means providing fluid-tight connections between said metal tank and said mounting means and between said metal tank and said expansion chamber.

2. In a fluid-tight housing for a circuit interruptr of the blast action are extinguishing type, in combination, means removably mounting the circuit interrupter in the housing, and an expansion chamber formed of insulating material-carried externally by said housing in such position as to receive the products of the arc resulting from the blast action.

3. A unitary housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a metal tank for receiving the interrupter, means at one end of said tank for removably mounting the circuit interrupter therein, and an insulated expansion chamber mounted at the other end of said tank for receiving the products of the arc resulting from the blast action.

4. A unitary housing for a circuit interrupteroi the blast action are extinguishing type comprising, in combination, a metal tank for receiving the interrupter, means at one end of said tank for removably mounting the circuit interrupter therein, an insulated expansion chamber mounted at the other end of said tank for receiving the products of the arc resulting from theed at the other end of said tank for receiving the products of the arc resulting from the blast action, and valve means operable as a result of said blast action to vent said expansion chamber to the surrounding atmosphere.

6. In combination, a metal housing for receiving a circuit interrupter of the blast action are extinguishing type, means for removably mounting the circuit interrupter in said housing, terminal means extending exteriorly of said housing to permit connection of the circuit interrupter in an electric circuit, and connector means arranged and adapted to cooperate with said terminal means for bridging the same and shunting the circuit interrupter.

7. In combination, a metal housing for receiving a circuit interrupter of the blast action are extinguishing type, means for removably mounting the circuit interrupter in said housing, a pair of terminal assemblies carried by said housing and each connected to a terminal of the circuit interrupter, and a pair of connector means forming a part of each terminal assembly and disposed externally of said housing, one of each of said connector means being adapted for connection to a circuit conductor and the other being adapted for connection to a conductor for shunting the circuit interrupter.

8. A housing for a circuit interrupter of the blast action are extinguishing type comprising,

in combination, a metal tank for the circuit interrupt r, insulating means carried by said tank for receiving the circuit interrupter and surrounding the same, and an insulated expansion chamber carried externally bysaid. tank in such position as to receive the products of the arc resulting from the blast action.

9. A housing for a circuit interrupter'o'f the blast action arc extinguishing type comprising, in combination, a metal tank arranged and adapted to receive the circuit interrupter, an expansion chamber formed of insulating material and carried by said tank in such position as to receive the products of the arc resulting from the blast action, and means providing a sealed connection between said expansion chamber and said tank.

10. A housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a metal tank arranged and adapted to receive the circuit interrupter, an expansion chamber formed of insulating material and carried by said tank in such position as to receive the products of the arc resulting from the blast action, sealing means between said expansion chamber and said tank to prevent the ingress of moisture, and additional sealing means between said expansion chamber and said tank to prevent the egress of said products of the arc.

11. A housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a metal tank arranged and adapted to receive the circuit interrupter, an expansion chamber formed of porcelain and carried by said tank in such position as to receive the products of the arc resulting from the blast action, means for clamping said expansion chamber onto said tank, outside gasket means between said chamber and said tank to prevent the ingress of moisture, and inside gasket means between said chamber and said tank to prevent the egress of said products of the arc.

12. A housing for acircuit interrupter of the blast action arc extinguishing type comprising, in combination, a metal tank arranged and adapted to receive the circuit interrupter, an expansion chamber formed of percelain and carried by said tank in such position as to receive the products of the are resulting from the blast action, a flange integrally formed with and extending outwardly from said porcelain expansion chamber, an annular clamp ring surrounding said expansion chamber with its faces parallel to said flange, a plurality of C-shaped clamp members cooperating with said tank and said clamp ring for holding said expansion chamber in position, sealing means between said flange and said tank to prevent the ingress of moisture, and additional sealing means between said expansion chamber and said tank to prevent the egress of said products of the arc.

13. A housing for a circuit interrupter of the blast action arc extinguishing type comprising, in combination, a metal tank arranged and adaptted to receive the circuit interrupter, an expansion chamber formed of porcelain and carried by said tank in such position as to receive the products of the arc resulting from the blast action, the face of said porcelain expansion chamber abutting said tank having an annular groove therein, means for clamping said porcelain expansion chamber onto said tank, an outside gasket between the outer lip of said groove and said tank adapted to resist the stress set up by said clamping means and to-prevent the ingress of moisture, and an inside gasket between the inner lip of said groove and said tank adapted to have intimate engagement with said inner lip to prevent the egress of said products of the arc.

14. A housing for a circuit interrupter of the blast action arc extinguishing type comprising, in combination, a metal tank arranged and adapted to receive the circuit interrupter, an expansion chamber formed of porcelain and carried by said tank in such position as to receive the products of the arc resulting from the blast action, the face of said porcelain expansion chamber abutting said tank having an annular groove therein and the outside and inside lips of said groove having toned surfaces, means for clamping said porcelain expansion chamber onto said tank, a relatively hard rubber gasket between the toned surface of said outer lip and said tank for resisting the stress set up by said clamping means and to prevent the ingress of moisture, and a relatively soft rubber gasket between the toned sur-" face of said inner lip and said tank to prevent the egress of said products of the arc.

15. A housing for a circuit interrupter of the blast action arc extinguishing type comprising, in combination, a metal tank arranged and adapt ed to removably receive the circuit interrupter, an insulated expansion chamber carried by said tank in such position as to receive the products of the arc resulting from the blast action, and valve means carried by said expansion chamber and operable on the generation of a-predetermined pressure therein to vent the same to the surrounding atmosphere.

16. A housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a metal tank arranged and adapted to removably receive the circuit interrupter, an expansion chamber formed of insulating material and hermetically sealed to said tank in such position as to receive the products of the are resulting from the blast action, and valve means carried by said chamber in line with the flow of said products of the arc and operable on the generationof a predetermined pressure therein to vent the same to the surrounding atmosphere.

1'7. A housing for a circuit interrupter of the blast action arc extinguishing type comprising, in combination, a metal tank arranged and adapted to removably receive the circuit interrupter, an expansion chamber formed of insulating material and hermetically sealed to said tank in such position as to receive the products of the arc resulting from the blast action, valve means carried by said chamber in line with the flow of said products of the arc and operable on the gen- 'eration of a predetermined pressure therein to vent the same to the surrounding atmosphere, and baiile means carried by said valve means and disposed directly in the path of said products of the are for initiating the opening of said valve means.

18. A housing for a generally cylindrically shaped circuit interrupter unit of the blast action are extinguishing type comprising, in combination, a metal tank, and a tubular insulator inside of and secured to said tank in a substantially vertical position for receiving the circuit interrupter unit.

19. A housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a cylindrical metal tank, and an insulating sleeve disposed coaxially with said tank inside thereof and secured thereto for receiving the circuit interrupter, said sleeve being of such length that its ends project beyond the ends of said tank.

20. A housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a cylindrical metal tank, a tubular insulator inside of and secured to said tank for receiving the circuit interrupter, and a pair of terminal assemblies carried by said tubular insulator in spaced apart relation and extending externally of said tank to permit connection to the circuit interrupter. i

21. A housing for a circuit interrupter of the blast action arc extinguishing type comprising, in combination, a cylindrical metal tank, an insulating sleeve disposed coaxially with said tank inside thereof and secured thereto for receiving the circuit interrupter, said sleeve being of such length that its ends project beyond the ends of said tank, a pair of terminals carried by said insulating sleeve in spaced apart relation for elecll trical connection to the circuit interrupter, and connecting means individual to each or" said terminals and extending externally of said tank to permit externm connection to the circuit interrupter.

22. A housing for a circuit interrupter oi the blast action arc extinguishing type comprising,

in combination, a cylindrical metal tank, a tubular insulator inside of and secured to said tank for receiving the circuit interrupter, and a filling of solidified insulating compound inside of said tank around said tubular insulator.

23. A housing for a circuit interrupter oi the blast action arc extinguishing type comprising, in combination, a cylindrical metal tank, an insulating sleeve disposed coaxially with said tank inside thereof and secured thereto for receiving the circuit interrupter, said sleeve being of such length that its ends project beyond the ends of said tank, and a filling of solidified insulating compound inside of said tank and around said insulating sleeve.

24. A housing for a circuit interrupter oi the blast action are extinguishing type comprising, in combination, a cylindrical metal tank, a tubular insulator inside of and secured to said tank for receiving the circuit interrupter, a filling of insulating compound inside of said tank around said tubular insulator, and a pair of .terminal assemblies carried by said tubular insulator in spaced apart relation and extending through said filling of insulating compound and said tank to permit external connection to the circuit interrupter.

25. Ahousing for a circuit interrupter oi the blast action are extinguishing type comprising, in combination, a cylindrical metal tank, an insulating sleeve disposed coaxially with said tank inside thereof and secured thereto for receiving the circuit interrupter, said sleeve being of such length that its ends project beyond the ends of said tank, a filling of solidified insulating compound inside of said tank and around said insulating sleeve, a pair of terminals disposed inside of said insulating sleeve in spaced apart relation for electrical connection to the circuit interrupter, and connecting means individual to each of said terminals and extending through said insulating sleeve, said filling of insulating compound and said tank to permit external con nection to the circuit interrupter.

26. A housing for a circuit interrupter of the blast.action arc extinguishing type comprising, in combination, a cylindrical metal tank, an insulated dome sealed to one end of said tank for receiving the products of the arc, a tubular insulator inside of and secured to said tank for re ceiving the circuit interrupter, and mounting means disposed to be sealed to the other end of said tank for removably mounting the circuit interrupter in said insulator.

2'7. A housing for a circuit interrupter of the blast action are extinguishingtype comprising, in combination, a cylindrical metal tank, an insulated dome sealed to one end of said tank for receiving the products of the arc, a tubular insulator inside of and secured to said tank for receiving the circuit interrupter, and mounting means disposed to be sealed to the other end of said tank for removably mounting the circuit interrupter in said insulator, said insulator being of such length that its ends project beyond the ends of said tank and into said dome at one end and into said mounting means at the other end.

28. A housing I0: a circuit interrupter of the blast action are extinguishing type comprising, in combination, a cylindrical metal tank, an insulated dome sealed to one end of said tank for receiving the products of the arc, a tubular insulator inside of and secured to said tank for receiving the circuit interrupter, mounting means disposed to besealed to the other end of said tank for removably mounting the circuit interrupter in said insulator, said insulator being of such length that its ends project beyond the ends of said tank and into said dome at one end and into said mounting means at the other, and a filling oi solidified insulating compound inside of said tank and around said insulator.

29. A housing for a circuit interrupter of the blast action are extinguishing type comprising, in combination, a cylindrical metal tank, an in sulated dome sealed to one end of said tank for receiving the products of the are, a tubular insulator inside of and secured to said tank for receiving the circuit interrupter, mounting means disposed to be sealed to the other end of said tank for removably mounting the circuit interrupter in said insulator, said insulator being of such length that its ends project beyond the ends of said tank and into said dome at one end and into said mounting means at the other, a filling of solidified insulating compound inside of said tank and around said insulator, and a pair of terminal assemblies carried by said tubular insulator in spaced apart relation and extending through said filling of insulating compound and said tank to permit external connection to the circuit interrupter.

30. A housing for an elongated circuit interrupter of the blast action are extinguishing type having external terminals comprising, in combination, a tank, an expansion chamber sealed to one end of said tank for receiving the products of the arc, an insulating sleeve mounted in said tank for receiving the circuit interrupter, a pair of terminal assemblies carried by said sleeve in spaced apart relation and extending externally of said tank, and mounting means disposed to be sealed to the other end of said tank for removably mounting the circuit interrupter in said sleeve with its terminals in contact engagement with said terminal assemblies.

31. A housing for an elongated circuit interrupter of the blast action are extinguishing type having external terminals comprising, in combi nation, a tank, an expansion chamber sealed to one end of said tank for receiving the products of the arc, an insulating sleeve mounted in said tank for receiving the circuit interrupter, a pair of terminal assemblies carried by said sleeve in spaced apart relation and extending externally of said tank, a support shell, means for sealing said support shell to the other end of said tank, and a pillar of insulation carried by said support shell and adapted to removably mount the circuit interrupter in said sleeve with its terminals in contact engagement with said terminal assemblies.

32. In a housing for a circuit interrupter of the blast action are extinguishing type having a vent cap adapted to be blown oil, in combination, means removably mounting the circuit interrupter in the housing, an insulated expansion chamber carried by said housing in such position as to receive the products of the arc resulting from the blast action, a condenser assembly carried by said housing between said circuit interrupter and said expansion chamber for cooling means disposed in the path of the vent cap and 

